138 lines
4.9 KiB
Markdown
138 lines
4.9 KiB
Markdown
---
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title: Object Files
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TARGET DECK: Obsidian::STEM
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FILE TAGS: linker::object-file
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tags:
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- linker
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- object-file
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---
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## Overview
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Object files come in three forms:
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1. **Relocatable object files**. Contains binary code and data in a form that can be combined with other relocatable object files at compile time.
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2. **Executable object files**. Contains binary code and data in a form that can be copied directly into memory and executed.
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3. **Shared object files**. A special type of relocatable object file that can be loaded into memory and linked dynamically, at either load time or run time.
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%%ANKI
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Basic
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What are the two types of object files?
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Back: Relocatable and executable.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1734356868367-->
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END%%
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%%ANKI
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Basic
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Relocatable object files are outputs of which compiler driver component?
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Back: The assembler.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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Tags: c17
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<!--ID: 1734356868394-->
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END%%
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%%ANKI
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Basic
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Executable object files are outputs of which compiler driver component?
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Back: The linker.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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Tags: c17
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<!--ID: 1734356868399-->
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END%%
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%%ANKI
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Basic
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Relocatable object files are inputs into which compiler driver component?
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Back: The linker.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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Tags: c17
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<!--ID: 1734356868403-->
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END%%
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%%ANKI
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Basic
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Executable object files are inputs into which compiler driver component?
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Back: N/A.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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Tags: c17
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<!--ID: 1734356868406-->
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END%%
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%%ANKI
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Cloze
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A {shared} object file is a special case of a {relocatable} object file.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1734356868428-->
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END%%
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An **object module** is a sequence of bytes whereas an **object file** is an object module stored on disk.
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%%ANKI
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Basic
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What is an object module?
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Back: A sequence of bytes.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1734356868413-->
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END%%
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%%ANKI
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Basic
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In terms of object modules, what is an object file?
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Back: An object module stored on disk.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1734356868418-->
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END%%
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%%ANKI
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Basic
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What distinguishes an object module from an object file?
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Back: An object file is an object module stored on disk.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1734356868423-->
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END%%
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%%ANKI
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Basic
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In what way is the term "object file" misused by Bryant et al.?
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Back: Technically this term only refers to object modules on disk.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1734356868433-->
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END%%
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Object files are organized to specific **object file formats**:
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* Windows uses the PE (Portable Executable) format.
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* Mac OS-X uses the Mach-O format.
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* Modern x86-64 Linux systems use the ELF (Executable and Linkable Format) format.
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%%ANKI
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Basic
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What object file format do x86-64 Linux machines typically use?
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Back: ELF.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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Tags: x86-64
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<!--ID: 1734356868437-->
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END%%
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%%ANKI
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Basic
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What is the ELF object file format an acronym for?
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Back: **E**xecutable and **L**inkable **F**ormat.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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Tags: x86-64
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<!--ID: 1734356868442-->
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END%%
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%%ANKI
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Basic
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What is ELF an example of?
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Back: An object file format.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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Tags: x86-64
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<!--ID: 1734356868446-->
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END%%
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## Bibliography
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* Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016. |